Cantilever arrayed blood pressure sensor for arterial applanation tonometry

We developed a cantilever-arrayed blood pressure sensor array fabricated by (111) silicon bulk-micromachining for the noninvasive and continuous measurement of blood pressure. The blood pressure sensor measures the blood pressure based on the change in resistance of the piezoresistor on a 5-μm-thick-arrayed perforated membrane and 20-μm-thick metal pads. The length and width of the unit membrane are 210 and 310 μm, respectively. The width of the insensible zone between adjacent units is only 10 μm. The resistance change over contact force was measured to verify the performance. The good linearity of the result confirmed that the PDMS package transfers the forces appropriately. The measured sensitivity was about 4.5%/N. The maximum measurement range and resolution of the fabricated blood pressure sensor were greater than 900 mmHg and less than 1 mmHg, respectively.